Loading and unloading of work in machine tools



y 1936. H. c. PIERLE 2,042,123

LOADING AND UNLOADING OF WORK IN MACHINE TOOLS Filed April 9, 1935 4 Sheets-Sheet 1 y 1936- i v Hfc. PIERLE I 2,042,123

LOADING AND UNLOADING OF WORK IN MACHINE TOOLS Filed April 9, 1935 4 Sheets-Sheet 2 Mt -M May 26, 1936. H C ER 2,042,123

LOADING AND UNLOADING OF WORK IN MACHINE TOOLS Filed April 9, 1955 4 Sheets-Sheet 3 May 26, 1936.

H. C. PIERLE LOADING AND UNLOADING OF WORK IN MACHINE TOOLS Filed April 9, 1935 4 Sheets-Sheet 4 Patented May 26, 1936 PATENT OFFICE LOADING AND .UNLOADING OF WORK IN MACHINE TOOLS Henry C. Pierle, Cinclnnati,, hlo, assignor to The R. K. Le Blond Machine Tool Company, Cincinnati, Ohio, a corporation of Delaware Appllcation April 9, 1935, Serlal No. 15,457

15 Claims.

This invention pertains to a work loading device for machine tools, more particularly to a class of machines known as center drive lathes;

and an object of the invention is to provide mechanism whereby a work piece is loaded and unloaded endwise through a center drive chuck or plurality of such chucks. More specifically it is an object of my invention to provide a pair of opposed centers, movable axially in synchronism, m such as may carry a crank shaft on the axis of its main bearings, which centers carry the work, while so held, endwise through the center drive chuck or chucks to a definite axial position either for gripping and location by the chucks in definite axial alignment with the centers and in definite index and driving relation to the chucks and the cutting tools, or for removal from the machine.

A further object of my invention is to apply such a loading device to a center drive lathe having a plurality of work spindles in such a-way that work may be loaded and unloaded independently on each spindle or simultaneously on all of the spindles.

Another object of my invention is to provide either hydraulic or mechanical means for actuating the centers axially in synchronism.

I have not shown a complete lathe since this is not required for a full explanation and understanding of my invention. For purposes of illusis in no way limited to such structure and may beapplied to any machine tool wherein its characteristics are desirable.

The objects of my invention which I have set 5 forth and others which will be mentioned hereinafter, or will be apparent to one skilled in the art upon reading these specifications, I accomplish by that certain construction and arrangement of parts and by that process of which I shall herein- 50 after describe the aforesaid exemplary embodiments. References made to the drawings wherein: a

Figure 1 is a front elevation of the machine with the work shown gripped in the center drive 5 chucks for the turning operation.

Figure 2 is a right hand end elevation, partly in section on line A-A of Figure 1.

Figure 3 is a diagrammatic illustration, partly in section, of hydraulic actuating mechanism for the centers.

Figure 4 is a diagrammatic illustration, partly in section, of mechanical actuating mechanism for the centers.

Referring now to the drawings, particularly Figure 1, the. base of the machine is indicated at 10 I. A right hand housing 2 and a left hand housing 3 are suitably secured to the base I by keys 4 and bolts 5. Between the -housings 2 and 3 are a series of center drive chuck units 6, tool holder units I, and end thrust plates 8 all properly held 15 the right hand unit 6 should the work prove too limber to withstand thecutting forces exerted by the tools. Properly designed tools I2, secured to the tool holders I, operate on the surfaces I3 of the crank shaft I4 as they are fed to the work by the motion of the tool holder units 1.

Referring now particularly to Figures 1, 2 and 3, the righthand housing 2 carries an integral boss I5. A rectangular slot I6 and a'semi-circular slot I I are provided for each work spindle. In

the horizontal surfaces of the rectangular slots I6 are accurately machined V-grooves or ways I8,

in exact parallelism with the axes of the work spindles, in which the slides. I9 are free to move longitudinally. Tubular members 20 carrying the centers 2| are mounted for longitudinal movement parallel with the work spindle axes by manual operation of handwheelsql through the shafts 22 and pinions 23, the pinions enga ing suitable racks 21 formed integral with the tu ular members 20. This mechanism is provl ed for the proper adjustment of the centers to variations in the longitudinal centering of the workpieces and to assistin placing the work on or removing it from the centers. Keys 25 are provided to prevent'turning of the tubular members 20 as the work is revolved. I

Hydraulic cylinders 26- are secured to the boss I5 by bolts 21 and have pistons 28 connected to the piston rods 29 which pass through the usual the members 46, 46 and 4|.

packing 36. The outer ends of the piston rods 29 are bolted at 3| to lugs 32 formed integral with the slides|9 and moving in the slots I1 so that as the pistons 28 are reciprocated under hydraulic pressure the slides l9 and centers 2| are also reciprocated therewith.

The spindles 33 are secured in the bores 34 and 35 in the left hand housing 3 by means of the nuts 36. The projecting ends 31 of the spindles 33 carry the hydraulic cylinders 36 secured thereto by threaded means at 39. The piston rods 46 are attached to pistons 4| in the hydraulic cylinders 38 and are carried through the usual packings 42 held in the ends 31 of spindles 33. Bushings 43 and 44 are provided in the bores 45 of spindles 33 in which the tubular members 46, carrying the centers 41, are free to slide longitudinally on the work spindle axes. The piston rods 40 are securely connected to the tubular members 46 by suitable means 48 so that as the pistons 4| and their rods 46 are reciprocated under hydraulic pressure, the tubular members 46 -49 are provided to limit the endwise travel to the left or loaded position of the centers 41 through This in turn limits the position of the work pieces l4 and the right hand centers 2| and their slides 9 and pistons 28. The limitation of the travel to the right or. to the unloaded position is provided by the pistons 4| striking against the surfaces 56 of the extensions 31 of spindles 33.

Fluid pressure for actuating the hydraulic cylinders 26 and 38 is derived from a standard commercial compound hydraulic pump consisting of a low pressure unit 5| and a" high pressure unit 52 driven bythe usual electric motor 53 through a coupling 54. An oil reservoir 55 is connected to the pumps 5| and 52 through lines 56 in order to keep the pumps primed at all times. A drain or return line 51 takes care of the discharge through the various relief valves.

The high pressure pump 52 delivers fluid through the line 63 to a distributing valve 64. As

illustrated in Figure 3, the plunger 65 of the valve 64 is to the left position 66. It can be clearly seen that in this position of the valve the high pressure fluid can pass from line 63 through chamber 61 of the valve 64 and through line 68 into the piston head chamber 69'of cylinder 26. This causes piston 28 to move to the left, moving the work l4 and piston 4| also to the left through the means already described. Oil is displaced valve 14. Consequently as the device moves longitudinally to the left, back pressure is built up against the pressure in the chamber 69 by a lesser pressure in the chamber 16 so as to prevent jump ing and to keep the work |4 securely held on the centers 2| and 41. When the longitudinal move-' ment to the leftis stopped by piston 4| striking.

the adjustable stop 49, theback pressure built up in chamber 69 is allowed (to escape through the high pressure relief valve 14.

The low pressure pump 5| keeps the piston rod chambers 58 and 59 of the respective cylinders 26- and 38 charged at all times with fluid pressure Such the centers longitudinallyin synchronism without having t the shut-off v ve 60a is closed.

When the piston of the valve 64 is moved to its right hand position 15, high pressure is applied in the chamber I6 and fluid is ejected from the chamber 69 through the line 68 and-bypassed through the medium pressure relief valve 16, which is identical with valve 13, thus causing the device to move longitudinally to the right until the piston 4| strikes the surface 56, as previously described. The pressure thus built up? escapes through the high pressure relief valve 14. The

ork inserted between the centers,

low pressure pump 5| and its circuit function the 1 same for either direction ,of movement of the device.

Suitable levers and linkage 11, I6 and 19 are provided so that the valve 64 may be controlled by the .foot, leaving the operator's hands free to place the work in, or remove it from the centers. As the pedal 86 is pushed down, the work I4 is moved endwise to the left into the chuck H, and it is moved endwise out of the chuck when the pedal 8| is pressed down. By using one valve 64 and control means 16 for each work' spinde, a' device may be operated independently on eachspindle. Shouldit be desirable to operate the devices on both spindles simultaneously, both devices may be connected in parallel to one valve 64 and control means 18. j

Referring now particularly to Figure 4, which shows a mechanical actuating mechanism for the centers, a plate 6| having a hub 62 iS secured by bolts 63 to the boss l5 of the right hand housing 2. A gear 84, which runs loose on the hub 62, is fastened to a; disc by means of bolts 86. A scre'viefl is pinnedat 66 to the disc 65 on the axial center of rotation of the gear 84 and disc 65. A suitable thrust collar 69 is secured to the screw by the pin 96 The screw operates in a nut 32a which is an integral part of the slide I9 so that as the gear 84 is rotated one way or the other; the slide may be similarly reciprocated longitudinally. t

In the bores 34 and 35 of the left hand housing 3 is held a spindle 9| by means of a nut 36. Bushings 43 and 44 are provided in the bore 45 of the spindle 9| in which the tubular member 92, carrying the center 4|,-is free to move axially. Threads 93 are provided in the rear end of the tubular. member 92 in which a screw 94 operates. A gear 64 runs loosely on an extension 95 of the spindle 9|, being held thereon by collar 64. Secured to the gear 84 by bolts 96 is a hub piece 91 also journaled on the extension 95. The screw 94 is pinned at 96 to the hub piece 91 on the axis of 'rotation of the gear 64 and the hub piece 91, so

' that as the gear 64 is rotated one-way or the other, the tubular member 92 with its center 41 is similarly reciprocated axially. Adjustable stop means 49 are provided forlimiting the'travel of the device to'the left, as was described in connection with the hydraulic controlling means.

I02, keyed to the other ends of the drive shaft I00, drive the gears 84 through idler gears I03 carried on studs I04 secured in the housings. The screws 81 and 94 are identical and of the same hand and, since the gear ratio between pinion I02 and gear 84 is the same on both housings 2 and 3, as the drive shaft I is revolved one way of the other, the centers 2| and 41 are reciprocated in synchronism with each other.

Reversible power means I05 are applied to the drive shaft I00 through suitable transmission gear means I06 and I01. A reversing switch I08 for the power means I05 is operated through a suitable treadle I09 connected by link IIO, bell crank II I and link I I2, this operating mechanism being similar to that described for the hydraulic unit.

Since the centering of the work may be a'ccomplished by chucks as well as by centers, it is to be understood that when I speak of centers, I mean any work holding means at the ends of the work piece.

It is to be understood that difi'erent forms of my preferred embodiment may be made without departing from the spirit of my invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:-

1. In a lathe provided with centers and with at least one center drive chuck adapted for axial loading, means in connection with said lathe centers for moving said work axially of said chuck to gripping and unloading positions, while said work move a work piece held therebetween axially of said chuck, to gripping and unloading positions. ,4. A lathe having head and tail stock centers and at least one center drive chuck, and means for moving said head and tail stock'centers simultaneously, whereby to move a work piece held therebetween axially through said chuck, said means comprising a mounting for one of said centers interspaced from the point of work engagement thereof, so that said center may be moved until said point of work engagement passes sub-, stantially through said chuck. a

5. In a lathe having head and tail stock centers and a center drive chuck, slidable mountings for said centers adapted to cause the work engaging portions of one of said centers, upon movement thereof, to pass substantially through said chuck, and means for moving said centers on said mountings in engagement with a work piece. '6. In a lathe having head and tail stock centers and a center drive chuck, slidable mountings for said centers adapted to cause the work engaging portions of one of said centers upon movement thereof, to pass substantially through said chuck, and means for moving said centers on said mountings in engagement with a work piece, said means comprising means for moving said centers simultaneously by like amounts, and means for exerting pressure on a work piece between said centers during said movement. 5

7. A lathe having a center drive chuck and an additional work holding means, and means for moving said work holding means while in an en- .gagement with said work in a direction axially of said chuck, so as to move said work to a position 10 lying substantially beyond said chuck, whereby said work may-{be removed from said lathe.

8. In a lathe aving hea d and tail stock centers and a ce ter drive chuck, means for synchronously moving said centers axially of said chuck to a position in which a work piece held therebetween will lie substantially beyond said chuck, said means comprising slidable mountings for said centers, fluid pressure actuating means therefore, and a synchronizing interconnection between said fluid pressure actuating means.

9. In a lathe having head and tail stock centers and a center drive chuck, means for synchronously moving said centers axially of said chuck to a position in which a work piece held therebetween will lie substantially beyond said chuck, said means comprising slidable mountings for said centers, fluid pressure actuating means therefonand a synchronizing interconnection between said fluid gressureactuating means, and means for exerting a back fluid pressure on one of said mountings during said movement.

10. In a lathe having head and tail stock centers between which a work piece is adapted to be supported, and a center drive chuck hydraulic means for moving one of said centers in the direction of the other center, additional hydraulic means actuated'by said first mentioned means, for moving said other center axially in the same direction as said first center, whereby said work piece held between said centers may be moved to a positionentirely outside said center drive chuck. i

11 In a lathe having head and tail'stock centers, hydraulic means for moving one of said centers in the direction of the other center, addition al hydraulic means actuated by said first mentioned means, for moving said other center axially in the same direction as said first center, and additional hydraulic means'providing a back pressure on at least one of said centers, whereby during conjoint movement of said centers an engaging pressure may be maintained upon a work piece held therebetween.

12. In a lathe having head and tail stock centers, means for moving said centers axially and in synchronism in either direction, said means comprising a motive means, a counter shaft driven thereby, and a pair of identical gear trains driven by said counter shaft, each of said gear 60 trains driving a lead screw of the same hand and nuts threaded on said screws, said head and tail A ,stock centers, respectively, connected to said nuts.

13. In a lathe having head and tail stock centers, each of said centers being connected by means of rods to pistons reciprocating in hydraulic cylinders, a supply of fluid under high pressure and a supply of fluid under low pressure, a distributing valve by means of which the high connection between the rod ends of the cylinders,

to which connection the source or low pressure fluid is constantly connected, whereby a back pressure is maintained on the cylinders and the axial movement of the centers in either direction' is accomplishedin exact synchronism.

14'. A lathe having head and tail stock centers and at least one center drive chuck, and means for moving said head and'tail stock centers sif multaneously, whereby to move a work piece held 10 therebetween axially of said chuck, and means for adjusting the relative position of one center with respect to the other. 1

15. In a lathe having a plurality of head and tail stock centers, means for producing axial movement of each pair of centers in either direction in synchronism whereby the center-tocenter distance of each pair is maintained constant during such movement, said means being independent for each pair of centers.

HENRY C. PIERLE. 

